Section 3: Shunting Signals

(Page 1 of 4)

Low speed shunting movements such as those to or from sidings or through crossover roads are governed by shunting signals. A shunting signal, when cleared, gives the driver authority to proceed cautiously as far as the line is clear, or to the next signal. The driver must understand that the line ahead may be occupied. A shunting signal may be associated with a main signal, in which case clearance of the shunting signal authorises the driver to pass the main signal at 'danger' (and vice versa). Most shunting signals are ground mounted, although some are elevated.

The first shunting signals evolved from points indicators (see Section 11). The points discs, which had been directly linked to the points and merely indicated their position, became signals in their own right. These 'independent discs' could show either a 'stop' or 'proceed' indication. The most basic form of disc signal displayed a circular red target in the 'on' position [3.1], it being rotated out of view when in the 'off' position [3.2]. At night, a red or green light was shown for the 'on' and 'off' indications, respectively. The Great Eastern Railway, the Highland Railway and the South Eastern Railway used this type of signal.

The London Brighton & South Coast Railway also used a shunting signal that displayed a red disc in the 'on' position (see [3.1]) but with the addition of a directing hand to show which line it applied to (see [27.1]). A second target was fitted for the 'proceed' indication, bearing a distinctive white cross on a green face [3.3].

The London & South Western Railway and the North British Railway both used a form of shunting signal that, in the 'on' position [3.6], presented a red face similar in shape to the LNWR signal (see [3.4]). These signals did not rotate however; to display the 'off' indication, the face dropped forward like a hinged flap [3.7].

The Caledonian Railway, the Great North of Scotland Railway and (from 1882) the Glasgow & South Western Railway used a similar 'flap' style of shunting signal to the L&SWR and the NBR but, when in the 'on' position, a rectangular face was displayed [3.8].

The Taff Vale Railway used a semaphore shunting signal with a centrally balanced arm [3.12 & 3.13]. They were painted with two white stripes, in common with the TVR's main semaphore signals (see [2.40 & 2.41]).

Some shunting signals on the Cambrian Railways took the form of a semaphore arm with a bulbous end [3.16 & 3.17], a feature more commonly associated with the railways of continental Europe. One such signal, at Aberdovey, survived into the British Railways era.

A special type of signal arm, sometimes known as a 'bow-tie', 'scissors' or 'skeleton' arm on account of its shape, was used by several companies to authorise shunting moves along a running line in the 'wrong direction' (i.e. against the normal direction of travel) [3.18 - 3.22].